In general, metallic cans typically used as the storage containers of beverage are mainly made from aluminum or iron materials.
FIG. 1 is a view showing a metallic can manufactured by a prior art method. As shown FIG. 1, the prior art metallic can is provided with a basic body 2 in the shape of a bottle having a bottle neck so that the prior art metallic can is called as a necking can.
The metallic can includes a sealing lip 3 provided to the outside surface of an upper end portion of the bottle neck part so as to carry out sealing of the metallic can through the coupling with a cap, a beading part 4 provided at the lower portion of the sealing lip 3 so as to check the opening of the cap, which is coupled for the sealing, and to carry out a pilfer-proof function, and a curling part 5 provided to the end portion of the bottle neck part so as to carry out finishing.
Additionally speaking, the metallic can as shown in FIG. 1 is formed with the body part 2 in the shape of a bottle having a bottle neck by carrying out drawing processing (cylindrical shape having a bottom surface) and necking processing with respect to a plate shaped material.
Then, the sealing lip 3 is formed by processing a coupling part in the shape of a screw on the outside surface of the upper end portion of the bottle neck part, and the beading part 4 is formed by carrying out beading processing at the lower portion of the sealing lip 3. Sequentially, the curling part 5 is formed by carrying out the necking processing twice at the end portion of the bottle neck part and carrying out flange forming and curling processing for folding and curling the end portion in the outward direction.
At this time, the procedure for forming the sealing lip 3 by processing the coupling part in the shape of a screw on the outside surface of the upper end portion of a metallic can 1 so as to be coupled with a cap is carried out by inserting an inside die in a screw shape to the inside of the inlet of the bottle neck part of the can 1, arranging an outside die to be in contact with the outside of the bottle neck part of the can 1, and forming the sealing lip 3 by simultaneously rotating the inside die and the outside die along the periphery of the can 1, wherein a step for forming the beading part 4 is additionally carried out at the lower portion of the sealing lip 3.
However, the prior art technique for processing the metallic can 1 as described above has a disadvantage that the manufacturing process of the metallic can 1 becomes complicated, deteriorating productivity because the process for forming the sealing lip 3 is separately carried out and the process for forming the curling part 5 also has to be additionally carried out after the sealing lip forming process.
In addition, the prior art technique for processing the metallic can 1 has another disadvantage that an additional equipment as well as an additional power supply means have to be provided for rotating the metallic can 1 because the metallic can 1 also rotates when the sealing lip 3 is formed through the rotation motion of the inside die and the outside die such that the sealing lip 3 is formed in the shape of a screw.